The importance of ponds
Scattered throughout Durham County are ponds. Some are large, some are small, some are old and some are brand new. They range from the old farm pond that has provided an irrigation source for nearby crops for more than 50 years (not to mention a great fishing spot), to the small neighborhood pond surrounded by suburban homes. One was built for crop-sustaining water and one was built half for aesthetics and half to treat stormwater runoff.
Their initial purposes might be different, but their benefit to the environment is the same no matter where they are.
I have often heard it said that ponds are one of the best Conservation BMPs (Best Management Practices) you can put on the land. Not only are they a source of water and a habitat for countless wildlife, but they also trap and treat sediment and nutrients. It is this job duty that is little-known and often overlooked, but of extreme importance to the entire watershed. If a local pond (be it urban or farm) is in place to intercept stormwater runoff after a heavy rain, that may be carrying eroded top soil (sediment) then that sediment will not continue on to the nearest stream, creek, river or lake. This sediment might also be carrying other pollutants such as fertilizers, pesticides and herbicides.
To trap and treat pollutants the pond, of course, captures the stormwater runoff full of sediment. Given enough time most sediments will settle to the bottom of the pond. Any fertilizer that is washed into the pond will be utilized by the aquatic plants living in and around the pond. The pond can then slowly release water back into the watershed that is much cleaner than when it went in, helping protect downstream bodies of water that are used as drinking water supplies. It is this capture-and-treat mechanism that is the principal factor behind those small, muddy-water-filled ponds you may see on the side of a road next to a major construction site. These sediment basins or sediment traps are regulated by law and often temporary, but they are essentially ponds and do what ponds do so well -- just without all the pretty plants and wildlife.
But as with any ecosystem, ponds can become unhealthy. They may be great at trapping and treating sediment, but as with anything, too much of something can also hurt you. While a healthy pond is an asset to the environment, an unhealthy pond can cause harm to the local environment. Too much sediment and too many chemicals and pollutants can overwhelm a pond’s natural ability to help the environment. These problems can be traced back to human activity upstream of the pond. But with proper care and management of the pond and the land that drains to the pond, a pond can last for generations.
Jennifer Brooks is soil conservationist/education coordinator with the Durham Soil and Water Conservation District, part of Durham County Government. Its mission is to conserve, enhance and promote the natural resources of Durham County by providing technical assistance, environmental education information and economic incentives to County citizens and by exhibiting a diversified program to meet its changing needs. For more information, visit http://dconc.gov/swcd or “like” on Facebook at http://www.facebook.com/pages/Durham-County-Soil-and-Water-Conservation-District/284665874878187 or “follow” on Twitter at http://www.Twitter.com/DCoSWCD.